'Black Carbon' Crackdown Offers Fast-Action Solution to Slow Warming

Lawmakers, scientists and advocates in the U.S. intensified calls Tuesday to immediately cut emissions from climate-warming soot — also known as black carbon — as deadlock continues in Congress over far more complicated regulation of carbon dioxide.

"Black carbon is an important, fast-action tool in mitigating long-term warming," said Veerabhadran Ramanathan, one of the world's leading climate scientists, in testimony before the House Select Committee for Energy Independence and Global Warming.

Although not a greenhouse gas, soot has emerged as a leading contributor to rising temperatures worldwide, scientists say. Limiting these emissions is seen as a relatively cheap and quick way to reign in warming in the short term.

Black carbon causes up to 600 times the warming of CO2 and lasts just a few weeks in the atmosphere, whereas CO2 lingers for a century or more. Because of black carbon's short lifespan, the impact of efforts to knock out the potent, heat-absorbing particle would be near immediate.

"Reducing black carbon emissions by 50 percent today will lead to a 50 percent reduction in the heat trapped by them within a few months," said Ramanathan, a professor at the Scripps Institute of Oceanography.

"Policymakers will witness the success of their actions during their tenure," he told the panel yesterday.

Climate experts estimate that black carbon pollution is responsible for roughly 20 percent of global warming, while CO2 accounts for half. Much of that soot comes from Asia and Africa, where cooking with primitive stoves and burning down forests and grasslands spews tons of the pollutant into the atmosphere. 

The U.S. contributes 5.5 percent to that global total, estimates say, mainly from diesel engines. Advocates argue the nation could easily shrink that number down to almost nothing, starting now. The filters to trap up to 90 percent of diesel pollution, for instance, are ready to go.

Fixes in developing countries are just as available, and at relatively little cost. They include replacing polluting cook stoves with solar-powered efficient ones at around $20 a pop, and reducing agricultural fires in the spring when Arctic ice is most affected by black carbon.

The solutions are "pretty simple" and "could be implemented without delay," said Conrad Schneider, advocacy director of the Boston-based Clean Air Task Force, during the hearing. Still, "relatively little is being done in the U.S. or globally to attack this problem," he said.

Missing: 'Mandates and Money'

In the U.S., Schneider leveled the blame at the federal government's lack of "mandates and money."

Last June, the U.S. House of Representatives passed the American Clean Energy and Security Act (ACES), also known as the Waxman-Markey bill, which incorporated a number of provisions to cut black carbon in America and seek opportunities to curb soot emissions abroad.

Specifically, the bill directs the U.S. Environmental Protection Agency (EPA) to propose regulations for black carbon within two years.

"Waxman-Markey made an excellent start in dealing with this issue," said Schneider. It is "a promising approach that deserves immediate attention."

But that bill — or any piece of comprehensive climate change legislation for that matter — appears all but dead in the U.S. Senate this year.

As Congress dawdles, the EPA has at least some authority to move. Under the Clean Air Act, the agency can retrofit filters on 1 million out of the 11 million old diesel engines in the United States. Citing an analysis by M.J. Bradley & Associates, Schneider said that adding a million traps would achieve the climate benefits of removing 21 million cars from the road.

"Yet, EPA has failed to act," said Schneider.

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